Microfracture: dead or the future?

Microfracture Augmentation With Trypsin Pretreatment and Growth Factor-Functionalized Self-assembling Peptide Hydrogel Scaffold in an Equine Model

BACKGROUND

Microfracture augmentation can be a cost-effective single-step alternative to current cartilage repair techniques. Trypsin pretreatment combined with a growth factor-functionalized self-assembling KLD hydrogel ("functionalized hydrogel") has been shown to improve overall cartilage repair and integration to surrounding tissue in small animal models of osteochondral defects.

HYPOTHESIS

Microfracture combined with trypsin treatment and a functionalized hydrogel will improve reparative tissue quality and integration as compared with microfracture alone in an equine model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Bilateral cartilage defects (15-mm diameter) were created on the medial trochlear ridge of the femoropatellar joints in 8 adult horses (16 defects total). One defect was randomly selected to receive the treatment, and the contralateral defect served as the control (microfracture only). Treatment consisted of 2-minute trypsin pretreatment of the surrounding cartilage, subchondral bone microfracture, and functionalized hydrogel premixed with growth factors (platelet-derived growth factor and heparin-binding insulin-like growth factor 1). After surgery, all horses were subjected to standardized controlled exercise on a high-speed treadmill. Clinical evaluation was conducted monthly, and radiographic examinations were performed at 2, 16, 24, 32, 40, and 52 weeks after defect creation. After 12 months, all animals were euthanized. Magnetic resonance imaging, arthroscopy, gross pathologic evaluation of the joint, histology, immunohistochemistry, and biomechanical analyses were performed. Generalized linear mixed models (with horse as random effect) were utilized to assess outcome parameters. When P values were <.05, pairwise comparisons were made using least squares means.

RESULTS

Improved functional outcome parameters were observed for the treatment group, even though mildly increased joint effusion and subchondral bone sclerosis were noted on imaging. Microscopically, treatment resulted in improvement of several histologic parameters and overall quality of repaired tissue. Proteoglycan content based on safranin O-fast green staining was also significantly higher in the treated defects.

CONCLUSION

Trypsin treatment combined with functionalized hydrogel resulted in improved microfracture augmentation.

CLINICAL RELEVANCE

Therapeutic strategies for microfracture augmentation, such as those presented in this study, can be cost-effective ways to improve cartilage healing outcomes, especially in more active patients.

Clinical and radiographic outcomes of chitosan-glycerol phosphate/blood implant are similar with hyaluronic acid-based cell-free scaffold in the treatment of focal osteochondral lesions of the knee joint

PURPOSE

To determine the clinical and radiographic efficacy of chitosan-glycerol phosphate/blood implant versus hyaluronic acid-based cell-free scaffold in patients with focal osteochondral lesion of the knee joint.

METHODS

Clinical data of 46 patients surgically treated using either chitosan-glycerol phosphate/blood implant (25 patients, Group 1) or hyaluronic acid-based cell-free scaffold (21 patients, Group 2) in combination with microfracture were retrospectively evaluated. All lesions were Outerbridge grade III or IV with a mean lesion size of 3.3 ± 0.7 cm². The mean follow-up time was 24.4 months. Visual analogue scale (VAS), Lysholm knee score, and Tegner activity scale were the instruments to evaluate the clinical status. Magnetic resonance observation of cartilage repair tissue (MOCART) system was used to analyze the characteristics of repair tissue.

RESULTS

No significant differences were detected between the groups regarding VAS, Lysholm, and Tegner scores at any time interval during the whole follow-up. The mean post-operative VAS and Lysholm scores at the latest follow-up was significantly better in cases with the lesion size ≤ 3 cm² in Group 1 (p = 0.001, p < 0.001, respectively). However, no significant differences according to the lesion size were detected in Group 2 (n.s.). Complete repair with the filling of the defect was achieved in 7 (28%) of the knees in Group 1 and it was 7 (33.3%) of the knees in Group 2 according to MOCART system at the latest follow-up.

CONCLUSION

Single-stage regenerative cartilage surgery using chitosan-glycerol phosphate/blood implant combined to microfracture for focal osteochondral lesions of the knee revealed similar clinical and radiographic outcomes with hyaluronic acid-based cell-free scaffold at short-term follow-up. However, clinical outcomes of hyaluronan scaffold were less sensitive to defect size than chitosan. With the advantages of no hypertrophic repair tissue formation as well as no need to arthrotomy during surgery, chitosan is an effective choice especially in patients with the lesion size ≤ 3 cm².

LEVEL OF EVIDENCE

III.

Prevention and management of post-instability glenohumeral arthropathy

Post-instability arthropathy may commonly develop in high-risk patients with a history of recurrent glenohumeral instability, both with and without surgical stabilization. Classically related to anterior shoulder instability, the incidence and rates of arthritic progression may vary widely. Radiographic arthritic changes may be present in up to two-thirds of patients after primary Bankart repair and 30% after Latarjet procedure, with increasing rates associated with recurrent dislocation history, prominent implant position, non-anatomic reconstruction, and/or lateralized bone graft placement. However, the presence radiographic arthrosis does not predict poor patient-reported function. After exhausting conservative measures, both joint-preserving and arthroplasty surgical options may be considered depending on a combination of patient-specific and anatomic factors. Arthroscopic procedures are optimally indicated for individuals with focal disease and may yield superior symptomatic relief when combined with treatment of combined shoulder pathology. For more advanced secondary arthropathy, total shoulder arthroplasty remains the most reliable option, although the clinical outcomes, wear characteristics, and implant survivorship remains a concern among active, young patients.

Results of Hyaluronic Acid-Based Cell-Free Scaffold Application in Combination With Microfracture for the Treatment of Osteochondral Lesions of the Knee: 2-Year Comparative Study

PURPOSE

To determine the clinical and radiographic efficacy of hyaluronic acid-based cell-free scaffold applied in combination with microfracture versus microfracture alone in patients with focal osteochondral lesion of the knee joint.

METHODS

Clinical data of 43 patients between 24 and 55 years of age were evaluated. Hyaluronic acid-based cell-free scaffold was applied in combination with microfracture for 19 knees (group 1), whereas microfracture alone was the surgical intervention for 24 knees (group 2). All lesions were Outerbridge grade III or IV with a mean size of 3.6 ± 1.3 cm². The mean follow-up time was 25.7 months. Visual analog scale (VAS), Lysholm knee score, and Tegner activity scale were the instruments used to evaluate the clinical status. Magnetic resonance observation of cartilage repair tissue (MOCART) system was used to analyze the characteristics of repair tissue.

RESULTS

Better VAS and Lysholm scores were detected in group 1 at 12 and 24 months (P = .019 and P = .025). According to the Tegner activity scale, group 1 had also better activity level at the end of 24 months after surgery (P = .020). The mean time from surgery to return to nonimpact sports activities was 7.8 months in group 1, whereas it was 9.2 months in group 2 (P = .013). Complete repair with the filling of the defect was achieved in 7 (36.8%) of the knees in group 1, whereas it was 4 (16.6%) of the knees in group 2 according to the MOCART system at 24 months.

CONCLUSIONS

Single-stage regenerative cartilage surgery using hyaluronic acid-based cell-free scaffold in combination with microfracture for focal osteochondral lesions of the knee revealed promising clinical outcomes at 24 months of follow-up, but the clinical significance of the differences seen is simply not known.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.